Multi-legend pushbuttons are used for indicating the state of a switch using multiple light sources and windows in the buttons to allow transmission of the light. In a simplistic example, a button may have a first window through which light from a first light source passes when an aircraft door is open, and a second window through which light from a second light source passes when the aircraft door is closed.
Previous multi-legend pushbuttons have lights with a lighting circuit integrated to the button cap—that portion of the pushbutton which moves when the pushbutton is actuated. The button lighting (typically light-emitting diodes (“LEDs”), and the corresponding lighting circuit, is therefore consolidated with the button caps and moves when the pushbutton is actuated. Each lighting circuit is electrically connected to a main circuit for at least the provision of power. The electrical connection must accommodate the movement of the button lighting relative to the main circuit.
In the example of a prior art pushbutton shown in FIGS. 1-3, the lighting and lighting circuit is provided on a flexible printed circuit board installed inside the button assembly. The flex circuit is soldered to a PCB of the main circuit (the main PCB) in order to provide legend lighting. The button cap is composed of opaque and transparent materials to isolate the light of the multiple light sources. One of the problems with such previous multi-illumination buttons is that the conductors and connections of the lighting circuit are mechanically stressed each time the pushbutton is actuated due to the button movement.